In some implementations, a rack management controller can dynamically manage power supply units in a server rack system. For example, the rack management controller can determine how many power supply units should be powered on based on the power requirements of the server rack system. The management controller can configure a power management controller to turn on the determined number of power supply units. The rack management controller can receive status signals from the power supply units in the server rack. The rack management controller can detect when a power supply unit fails based on the status signals. The rack management controller can dynamically reconfigure the power management controller to replace the failed power supply unit by turning on a reserved power supply unit.